A radio-frequency (RF) power amplifier is a type of electronic amplifier used to convert a low-power radio-frequency signal into a larger signal of higher power, typically for driving the antenna of a transmitter. Some performance criteria for the power amplifier include high efficiency, high output Power (PldB) compression, good return loss on the input and output, good gain, and good heat dissipation characteristics.
The basic applications of the RF power amplifier include driving to another high power source, driving a transmitting antenna, and exciting microwave cavity resonators. Among these applications, driving transmitter antennas is a widely used application. Some power amplifiers in transmitter-receivers are used for voice and data communication in various applications.
Power amplifiers are also commonly used in wireless devices to amplify a signal for transmission. Power amplifiers may include a final gain stage, referred to as an output gain stage, to amplify the signal to a desired power level for its output to a load such as an antenna that radiates the amplified signal. A power amplifier having a good performance under a relatively low power supply voltage is desired in some applications such as wireless devices.